AO Smith Water Heaters
Review and Buying Tips

Explore the benefits of the most popular and advanced AO Smith water heaters. Find the electric and gas models' review, including hybrid, tank, and tankless type, for heating domestic water.

Explore the benefits of the most popular and advanced AO Smith water heaters. Find the review of the electric and gas models, including hybrid, tank, and tankless type, for heating domestic water.

AO Smith is one of the largest manufacturers of water heaters in North America. For over 70 years, AO Smith is designing and producing HVAC equipment with numerous patents, models, and brands in their possession.

AO Smith water heater

The most advanced models are coming from the Vertex and Voltex series, including tank-type water heaters with condensing and heat pump technology, also tankless and POU type.

If looking for the best model, you can search for one with the cutting-edge technology and most advanced features, or check out the AO Smith catalog or brochure where the company already classified them as the "GOOD", "BETTER" and "BEST". This is what makes your search easy.

AO Smith water heater review

Choose a type

All gas and electric powered water heaters from AO Smith are grouped in the following three categories:

  • ProLine – cheap, low efficiency, and shorter warranty (promoted as GOOD) 
  • ProLine Master – affordable, better efficiency, and longer warranty (promoted as BETTER)
  • ProLine XE – lowest operating costs, expensive, longest warranty, and premium features (promoted as BEST)

Proline standard models recommended for small and average size homes have the highest operating costs and lowest warranty. In contrast, ProLine XE models, which are ideal for average and large homes, have the lowest operating costs and gas emission, and the warranty is long (up to 10 years on heat pumps and 15 years on tankless).

AO Smith gas water heaters

Gas water heaters from AO Smith are designed in many types and models; atmospheric, power vent, direct vent, power direct vent, high efficient, low NOx, high capacity, fast recovery, tankless and more, and for any home sizes and hot water demand. From the economy to highly advanced Vertex models that AO Smith makes – select the best one that fits all your needs for hot water and at the same time can save and last.

If looking for the best gas tank-type water heater for your large home and ultra-high efficient water heating, consider Vertex. AO Smith Vertex series offers several models and two sizes, all utilizing condensing technology, power vent, and power direct vent option.

They include commercial-grade elements such as the spiral heat exchanger, advanced electronics, side taps for recirculation, two heavy-duty anodes, and more. These can achieve ultra-high efficiency of over 96%, which maximizes savings.

AO Smith Polaris is another group of ultra-efficient tank-type water heaters with condensing technology and is recommended for those who want the best. Models come with stainless steel construction, modulating gas burner, and premium features, making it one of the preferable models to buy. They offer impressive specs, such as the first-hour rate of over 179 gallons, recovery rate up to 253 gallons, and an efficiency rate of 96%.

AO Smith electric water heaters

If natural gas and LP water heaters are not a good solution for your home, or gas is not available, then electric water heaters might be. They are cheaper, simpler, easy to install and maintain. Electric water heaters are mainly built for the whole house water heating. Still, there are also models such as Lowboy, Compact, Table Top, and small point-of-use models with a lower capacity and are meant for special applications.

The best models come from the Proline XE group, available in sizes from 40 to 55 gallons and designed tall or short, to use them in homes with 2-4 people. They utilize the electronic user interface with the touch screen, diagnostic system, and multiple operating modes for user convenience.

Read more about AO Smith electric water heaters.

Heat pumps

AO Smith Voltex heat pumps are the best from electric-powered water heaters because they come with an ultra-high-energy factor, Energy Star qualifications, and some unique features and specs. Users will enjoy a substantial reduction in water heating costs, multiple choices of operating modes, a user-friendly electronic interface for better accuracy, easier diagnostics, comfort, and convenience.

AO Smith heat pumps can be found in three sizes, with a tank capacity from 50 to 80 gallons, warranties of 6 and 10 years, and an energy factor that is more than three times higher than the efficiency of the standard electric type.

Read more about Voltex heat pumps.

Features of tank-type heaters

The majority of the electric and gas-powered AO Smith hot water heaters are designed with the following commercial-grade features:

DynaClean system is a self-cleaning system that reduces the sediment build-up while increasing the heater's performance. It is built from rigid materials to withstand high temperatures and resist premature failure due to water chemistry.

Green-Choice gas burner is an environment-friendly burner that is designed to reduce NOx emissions by 33%.

CoreGuard anode rod is a magnesium or aluminum rod with a stainless steel core, used to protect the tank from aggressive water action. It helps increase the longevity of the metal storage tanks. Top models usually have one heavy-duty anode or multiple rods so that the manufacturer can include longer warranties.

Blue Diamond glass coating is used to protect the inside surface of the tank from corrosion. This is another commercial-grade feature that works together with the anode to protect the metal tank from corrosion.

Other quality components found in AO Smith water heaters are the brass drain valve with enhanced flow, heat traps that help in energy loss reduction, electric heating elements and gas valves equipped with the microprocessor, and LED status indicator.


If you're looking for gas heaters that can produce hot water on demand and with the continuous water flow, AO Smith water heaters with tankless technology might be the solution for you.

AO Smith tankless units for residential water heating are small and wall-hanging, and due to their high-efficient operation are Energy Star approved. AO Smith tankless water heaters are designed for indoor and outdoor installation. They can supply enough hot water from smaller homes to larger houses with multiple bathrooms based on different water flow and power.

When we talk about specs, AO Smith tankless is amazing. They heat water using the powerful eco gas burners with up to 199,900 BTU gas input, reaching high efficiency of up to 0.96, and delivering up to 10 GPM of hot water, making them ideal for homes with multiple baths. They are backed by a 15-year warranty.

Check out our detailed review to see different types such as the ultra-low NOx non-condensing and condensing, tankless with the limescale prevention and recirculation, and find out the differences, benefits, and advantages over other types.

AO Smith also has a solution for those homeowners looking for more power and ultra-efficient water heating. These water heaters are known as condensing, and as the non-condensing units, they are eligible for government tax credits. Condensing technology is found not only in the storage tank type but tankless too.


Residential boilers from AO Smith are built to heat domestic water and home space as well. Boilers are similar to tankless; they utilize the flat plate heat exchanger and fire tube, both made of stainless steel, built-in recirculation pump, LCD display, and diverter valve to direct water either for water or space heating, using the external space heating loop.

All the models are built for indoor installation only, and due to their eco-friendly burner, they meet ultra-low NOx requirements. The warranty is 10 years.

About the company

AO Smith is the owner and manufacturer of the following brands:

AO Smith's corporate office is at 500 Tennessee Waltz Parkway, Ashland City, TN 37015, USA, and the phone number is 800-527-1953.


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